Vacuum pump



VACUUM PUMP Filed May 11, 1935 3 Sheets-Sheet 1 INVENTOR. f/FW/N 1". Lowe/r5 ATTORNEY.

July 28, 1936. E. F. LOWEKE VACUUM PUMP Filed May 11, 1933 3 Sheets-Sheet 2 Q 1 O L T$ 5, NW mw Q. QEIW.

ATTORNEY.

July 28, 1936. 1 F. LOWEKE IACUUM PUMP Filed May 11, 1933 3 Sheets- Sheet 3 v Q I INVENTOR. fRw/N E LOWE/(E flyim ATTORNEY.

Patented July 28, 1936 UNITED STATES PATENT. OFFICE VACUUM PUMP Erwin F. Loweke, Detroit, Mich., assignor to Hydraulic Brake Company, Detroit, Mich., a corporation of California Application May 11, 1933, Serial No. 670,613

3 Claims.

This invention relates to pumps and more particularly to vacuum pumps of the rotary type.

Broadly the invention comprehends a vacuum pump having one rotating element eccentrically located in a suitable casing and provided with a plurality of blades, free to slide tangentially with respect to the rotor. Because of the frictional engagement of the blades with the casing and their tangential relation to the rotor, there is a. tendency to draw the blades outward rather than to move them outward by centrifugal force. The blades are preferably formed in two parts, one slidable upon the other, to efiectively take up clearance between the blades and the wall of the casing.

Associated with the pump is a casing including an oil reservoir and an air chamber and passages leading from the reservoir and chamber, respectively, to the pump. The chamber is adapted to be connected to pipe lines or a chamber to be evacuated, and air and oil are drawn concurrently from the chamber and reservoir, respectively, into the pump casing and discharged therefrom into the reservoir, which is provided with means for extracting the oil from the air preparatory to discharging the air to the atmosphere.

An object of the invention is to provide a vacuum pump comprising a single rotor having blades movable tangentially thereto.

Another object of the invention is to provide a vacuum pump including a single rotor having blades movable tangentially thereto, each blade being formed of two parts, slidable one upon the other to take up clearance.

Another object of the invention is to provide a blade for a rotor including two parts, one slidable on the other.

Another object of the invention is to provide a blade for a rotor comprising two wedge shaped members, one slidable on the other, with means for reducing friction between the members.

A further object of the invention is to provide a vacuum pump including a single rotor provided with a plurality of blades, means for feeding air. and oil to the pump concurrently, and means for discharging the air and oil from the pump including means for separating the oil from the air.

Yet a further object of the invention is to provide a vacuum pump including a single rotor having a plurality of blades arranged to move tangentially thereto, a casing associated with the pump including an oil reservoir, and an air chamber and passages leading therefrom to the pump, a passage leading from the pump to the reservoir, and means in the reservoir for extracting the oil from the air prior to discharging the air to the atmosphere.

Other objects and structural details will appear from the subjoined description taken in connection with the drawings forming a part of this specification, and in which,-

Figure 1 is a side elevation of a pump embodying the invention;

Figure 2 is a vertical sectional view substantially on line 22, Figure 3;

Figure 3 is a sectional view substantially on line 3--3, Figure 2;

Figure 4 is a sectional view substantially on line 44, Figure 5;

Figure 5 is a sectional view substantially on line 5-5, Figure 4;

Figure 6 is a perspective view of one of the blades of the pump, and

Figure '7 is a perspective View of a modifica tion of the blades.

Referring to the drawings for more specific the top of the casing. The reservoir has a filling opening closed by a plug 18, and a drain opening closed by a plug 20. The chamber l6 has adjacent its top an air inlet port 22 communicating with a sleeve 24 formed on the wall of the chamber and internally threaded for the reception of a conduit which may lead to a chamber to be evacuated, and arranged within the chamber on the side wall thereof is a boss 26 extending at an incline from the bottom of the chamber near the back wall to the front wall. This boss is bored to provide a passage 28 extending through the front wall of the chamber.

As shown, the reservoir has formed in the bottom thereof a boss 30 extending from the front wall of the reservoir to substantially the center of the reservoir where it terminates in a perpendicular boss 32, the upper end of which is integral with a transverse boss 34 connecting the front and back walls of the reservoir. The bosses 30 and 32 are bored to provide a passage 36 extending through the front wall of the reservoir and communicating with the interior of the reservoir, and the boss 34 has a bore 38 extending through the front and back walls of the reservoir and intersecting the passage 36. The reservoir also has formed therein a boss 40 bored to provide a passage 42 leading from the interior of the reservoir through the front wall of the reservoir.

The reservoir has formed therein immediately above the filling opening a shoulder 44* providing a, support for a perforated diaphragm or baflie plate 48, preferably concave; and a shoulder 48 adjacent the top of the reservoir providing a support for a perforated diaphragm or bafile plate 58, also concave. The space in the reservoir between the baille plates 46 and 58 is filled with suitably absorbent material 52, the purpose of which'will hereinafter appear. V

The reservoir I4 and the chamber l8 are *closed as by a cover plate 54. The plate has a dome 58 arranged immediately above the reservoir. The top of the dome has an opening in which is fitted a perforated convex diaphragm or baflle plate 58, and fitted in the dome at the base thereof is a perforated concave diaphragm or baille plate 88 secured against displacement by a lock ring 82. The space between the diaphragms 58 and 88 is filled with a suitably absorbent material 84. and arranged between the diaphragms and 88 is a coil spring 88 for retaining the diaphragm 58 on the shoulder 48.

. The front or face of the casing is machined to provide a smooth, polished, circular, countersunk surface 88 arranged eccentrically to the bore 38. Formed on the back of the casing concentric to the bore 38 is a sleeve I8 having a double diametral bore providing an internal shoulder I2, and a duct I4 provides a communication between the sleeve and the reservoir I4.

Fitted on the face of the casing is a cylindrical pump casing I8 providing a chamber I8. The' casing I8 has in its wall an air inlet port 88 communicating with the air passage 28 leading from the bottom of the chamber I8 and an the airified oil. The pump chamber is provided with a cover plate 98, and bolts 82 threaded in the wall of the casing I8 pass through the wall of the casing-I8 and the cover plate so to secure these elements in position.

Positioned for rotation in the bore 38 is a shaft 94 provided with spaced circumferential grooves 98 and 98 connected by aspiral groove I88. The shaft has thereon an oil retaining washer I82 suitably held in close engagement with the shaft as by a split ring I84. The oil retaining washer is secured on the shoulder I2 in the sleeve I8 by a collar I88 sleeved on the shaft and threaded into the sleeve I8. p

The shaft 94 is adapted to be driven by any suitable motive power, and threaded on the free end of the shaft within the chamber 18 is a rotor I88 preferably drilled parallel to its axis to lighten the structure. The rotor is concentricwith respect to the shaft 94 and is eccentricallypositioned in the chamber, and the respective faces engagement of the outer ends of the blades with the wall of the pump chamber, sufllcient drag up by the spiral groove I88 to lubricate the shaft.

is imposed on the blades to draw them outwardly rather than to cause outward movement due to centrifugal force.

The blades 2 are preferably made in two parts, H4 and H8, slidable one upon the other to take up clearance between the blades and the end walls of the pump chamber. The preferred type of blade includes two wedge shaped members arranged in reverse position and flat one against the other. In this type one of the members is preferably grooved or channeled as at H8 to reduce friction. In another desirable type of blade, shown in Figure 7, a rectangular member is cut diagonally at I28 and assembled with the respective diagonal edges abutting one another.

In operation, assuming that the pump is properly installed and filled with oil to the level of the filling opening, upon movement of the rotor I88 in the direction indicated by the arrow, air is drawn in through the port 22, the chamber I8, 20

the passage 28, and the port 887to the pump chamber, and simultaneously therewith oil is drawn from the reservoir I4 through the passage 42 and the port 82 to the pump chamber where it serves to cool and lubricate the rotor, the 25 Excess oil which may pass beyond the circumferential groove 88 in the shaft and into the sleeve I8 is returned to the reservoir through the duct I4.

The'oil returning to thereservoir through the passage 38'drops to the level of the oil in the reservoirand the air and aerated oil passes upward through the diaphragm or baflie plate 48, the diaphragm or baflle plate 58, and the absorbing material between these members, where the heavier particles of oil are extracted from the air and seep downward through the absorption ma terial into the reservoir. The finer or light particles of oil in the air are extracted as the air is forced through the'space above the diaphragm 58 against the diaphragm88, and through the, diaphragms or baflle plates 58 and 88, and absorption material 84 between-these plates.

Due to a diflerential'pressure in'the reservoir I4 and the chamber I8 and vacuum line connected to the chamber, and to a tendency of this pressure to equalize itself upon stopp the pump, oil is drawn from the reservoir I4 through the pump to the chamber I8 where it is trapped and thus prevented from entering the vacuum line. Upon subsequent operations of the pump air is drawn through the port 22 and evacuates the oil from the chamber I8 and circulates it back through the pumpto the reservoir I4.

Although this invention has been described with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited by the scope of the appended claims.

Having thus described the various features of the invention what I claim as new and desire to secure by Letters Patent- Is:

. 1. A vacuum pump comprlsing an oil reservoir,

an air chamber, a filter in the reservoir open to 78 atmosphere, a shaft extending through the reservoir, a pump chamber having an oil inlet port communicating with the reservoir, an air inlet communicating with a passage opening into the airvchamber adjacent the bottom thereof, and a discharge port communicating with a passage in the wall of the reservoir and opening into the reservoir beneath the filter, and a rotor on the shaft within the pump chamber.

2. A vacuum pump comprising a reservoir having a filling opening and an outlet port, a filter in the reservoir, an air chamber associated with the reservoir having an inlet port and an outlet passage extending upwardly from adjacent the bottom thereof, a shaft extending transversely through the reservoir, a pump chamber having an air inlet port communicating with the outlet passage of the air chamber, an oil inlet port communicating with the outlet port of the reservoir, and a discharge port communicating with a passage in the wall of the reservoir opening into the reservoir beneath the filter, a rotor on the shaft within the pump chamber, and blades movable in slots in the rotor. "F i 3. A vacuum pump comprising an oil reservoir having a filling opening and a discharge port, a filter in the reservoir, a cover for the reservoir 5 having a dome opening to atmosphere, a filter in the dome arranged in spaced relation to the filter in the reservoir, an air chamber associated with the reservoir having an inlet port and an outlet passage extending upwardly from adjacent the bottom thereof, a shaft extending through the reservoir, a pump chamber mounted on the reservoir beneath the filter, and a rotor on the shaft and having an air inlet port communicating with the outlet passage of the air chamber, an inlet port communicating with the outlet port of the reservoir, and a discharge port communicating with a passage opening into the reservoir beneath the filter therein, a rotor on the shaft within the pump chamber, and blades movable 20 on the rotor.

ERWIN F. LOWEKE. 

